Method for forming semiconductor package structure with twinned copper layer

Abstract

A semiconductor package structure is provided. The semiconductor package structure includes a chip structure. The semiconductor package structure includes a first conductive structure over the chip structure. The first conductive structure is electrically connected to the chip structure. The first conductive structure includes a first transition layer over the chip structure, and a first conductive layer on the first transition layer. The first conductive layer is substantially made of twinned copper.

What is claimed is: 
     
       1. A method for forming a semiconductor package structure, comprising:
 performing a pulse electroplating process over a chip structure to form a transition layer over the chip structure, wherein the transition layer comprises twinned copper; 
 performing a direct current electroplating process on the transition layer to form a first conductive layer over the transition layer, wherein the first conductive layer is substantially made of twinned copper; and 
 after the formation of the first conductive layer, forming a second conductive layer over the first conductive layer, wherein a first average roughness of a first top surface of the second conductive layer is less than a second average roughness of a second top surface of the first conductive layer. 
 
     
     
       2. The method for forming a semiconductor package structure as claimed in  claim 1 , wherein the chip structure comprises a conductive feature, and the method further comprises:
 before the formation of the transition layer, forming a dielectric layer over the chip structure, wherein the dielectric layer has an opening exposing the conductive feature of the chip structure; 
 forming a seed layer over the dielectric layer and the conductive feature; 
 forming a mask layer over the seed layer, wherein the mask layer has a trench exposing a portion of the seed layer over the conductive feature, and the transition layer is formed over the portion of the seed layer; and 
 after the formation of the first conductive layer, removing the mask layer and the seed layer under the mask layer. 
 
     
     
       3. The method for forming a semiconductor package structure as claimed in  claim 1 , wherein the formation of the transition layer and the formation of the first conductive layer use a same electroplating solution and are performed in a same plating tank. 
     
     
       4. The method for forming a semiconductor package structure as claimed in  claim 1 , wherein the formation of the transition layer and the formation of the first conductive layer use a first electroplating solution, the formation of the second conductive layer use a second electroplating solution, and the first electroplating solution is different from the second electroplating solution. 
     
     
       5. The method for forming a semiconductor package structure as claimed in  claim 1 , further comprising:
 providing a molding layer surrounding the chip structure before performing the pulse electroplating process over the chip structure, wherein the transition layer is further formed over the molding layer. 
 
     
     
       6. The method for forming a semiconductor package structure as claimed in  claim 5 , wherein a twinned copper volume percentage in the transition layer increases in a direction away from the chip structure and the molding layer. 
     
     
       7. The method for forming a semiconductor package structure as claimed in  claim 1 , wherein the transition layer and the first conductive layer together form a conductive line. 
     
     
       8. The method for forming a semiconductor package structure as claimed in  claim 1 , wherein the twinned copper in the first conductive layer comprises (111)-oriented twinned copper. 
     
     
       9. The method for forming a semiconductor package structure as claimed in  claim 1 , further comprising:
 forming a dielectric layer over the chip structure before performing the pulse electroplating process over the chip structure, wherein the transition layer and the first conductive layer are formed over the dielectric layer and extend through the dielectric layer to be electrically connected to the chip structure, and the dielectric layer is in direct contact with the chip structure. 
 
     
     
       10. A method for forming a semiconductor package structure, comprising:
 providing a chip structure and a molding layer surrounding the chip structure; 
 performing a first pulse electroplating process over the chip structure and the molding layer to form a first transition layer over the chip structure and the molding layer, wherein the first transition layer comprises twinned copper; 
 performing a first direct current electroplating process on the first transition layer to form a first conductive layer over the first transition layer, wherein the first conductive layer is substantially made of twinned copper, the first conductive layer is thicker than the first transition layer, and the first transition layer and the first conductive layer together form a first conductive line; and 
 forming a second conductive layer over the first conductive layer, wherein an average volume percentage of the twinned copper in the first conductive layer is greater than an average volume percentage of the twinned copper in the second conductive layer. 
 
     
     
       11. The method for forming a semiconductor package structure as claimed in  claim 10 , further comprising:
 forming a seed layer over the chip structure and the molding layer before performing the first pulse electroplating process over the chip structure and the molding layer, wherein the first transition layer is formed over the seed layer, and the seed layer is in direct contact with the chip structure and the first transition layer. 
 
     
     
       12. The method for forming a semiconductor package structure as claimed in  claim 10 , further comprising:
 forming a second conductive line over the first conductive line after the first conductive line is formed, wherein a first average line width of the first conductive line is less than a second average line width of the second conductive line, and the second conductive line is in direct contact with the first conductive line. 
 
     
     
       13. The method for forming a semiconductor package structure as claimed in  claim 12 , wherein the formation of the second conductive line over the first conductive line comprises:
 performing a second pulse electroplating process over the first conductive line to form a second transition layer over the first conductive line, wherein the second transition layer comprises twinned copper; and 
 performing a second direct current electroplating process on the second transition layer to form a third conductive layer over the second transition layer, wherein the third conductive layer is substantially made of twinned copper, the third conductive layer is thicker than the second transition layer, and the second transition layer and the third conductive layer together form the second conductive line. 
 
     
     
       14. The method for forming a semiconductor package structure as claimed in  claim 10 , wherein the formation of the first transition layer and the formation of the first conductive layer use a same electroplating solution and are performed in a same plating tank. 
     
     
       15. The method for forming a semiconductor package structure as claimed in  claim 10 , wherein a twinned copper volume percentage in the transition layer increases in a direction away from the chip structure and the molding layer. 
     
     
       16. A method for forming a semiconductor package structure, comprising:
 providing a chip structure, a conductive via structure, and a molding layer surrounding the chip structure and the conductive via structure; 
 performing a pulse electroplating process over the conductive via structure and the molding layer to form a first transition layer over the conductive via structure and the molding layer, wherein the first transition layer comprises twinned copper; and 
 performing a direct current electroplating process on the first transition layer to form a first conductive layer over the first transition layer, wherein the first conductive layer is substantially made of twinned copper, and the first transition layer and the first conductive layer together form a first conductive line, and an average volume percentage of the twinned copper in the first conductive layer is greater than an average volume percentage of the twinned copper in the first transition layer. 
 
     
     
       17. The method for forming a semiconductor package structure as claimed in  claim 16 , further comprising:
 forming a seed layer over the conductive via structure and the molding layer before performing the pulse electroplating process over the conductive via structure and the molding layer, wherein the first transition layer is formed over the seed layer, and the seed layer is in direct contact with the conductive via structure and the first transition layer. 
 
     
     
       18. The method for forming a semiconductor package structure as claimed in  claim 16 , wherein the conductive via structure comprises a second transition layer and a second conductive layer, the second conductive layer is between the second transition layer and the first conductive line, the second transition layer comprises twinned copper, and a twinned copper volume percentage in the second transition layer increases toward the second conductive layer. 
     
     
       19. The method for forming a semiconductor package structure as claimed in  claim 18 , wherein the second conductive layer comprises twinned copper. 
     
     
       20. The method for forming a semiconductor package structure as claimed in  claim 16 , further comprising:
 forming a dielectric layer over the chip structure, the conductive via structure, and the molding layer before performing the pulse electroplating process over the conductive via structure and the molding layer, wherein the first transition layer and the first conductive layer are formed over the dielectric layer and extend through the dielectric layer to be electrically connected to the conductive via structure, and the dielectric layer is in direct contact with the chip structure.